An Effective Method for Screening and Testing the True Phosphate-Solubilizing Fungus That Enhances Corn Growth

Abstract

The effect of large-scale application of phosphate-solubilizing microorganisms (PSMs) on the promotion of crop growth varies. Usually the solubilization of tricalcium phosphate is considered as the standard for screening most PSMs. This study aimed to establish a common method for screening and testing true PSMs. The isolated fungus's phosphate-solubilizing ability, adaptation to corn root exudates, organic acids secreted, and colonization ability were analyzed. And the microorganism's diversity and ability to promote corn growth were also tested through plot experiment. The isolated fungus Aspergillus niger H1 (A-H1) was isolated and identified from plant rhizosphere that could solubilize phosphate, utilize corn root exudates as sources, and propagate well in vitro and soil. Lactic acid was excreted and reached 377.9 μg mL -1 at 30 h in culture by A-H1, which decreased the pH of culture to 1.73. The amount of A-H1 increased by 41-fold in 28 d and was maintained for 49 d. PSM showed selectivity on the transformation of different forms of P.However, a wide range of insoluble phosphates, such as Ca 8 H 2 (PO 4 ) 6 ·5H 2 O, AlPO 4 , FePO 4 , and Ca 10 (PO 4 ) 6 (OH) 2 , was converted to soluble CaHPO 4 in soil.CaHPO 4 was also inhibited from being converted into insoluble phosphate by A-H1. Corn yield increased by 10.71% that remarkable higher than the control after A-H1inoculation. Data show that A-H1 could propagate well, solubilize phosphate in soil, and promote corn growth. A common method was created to screen and test a true phosphate-solubilizing fungus that enhances plant growth.

Phosphate Solubilization Potential of Rhizosphere Fungi Isolated from Plants in Jimma Zone, Southwest Ethiopia

“…Acidification by organic acid has been reported to be the main solubilization mechanism of inorganic P by microorganisms [ 46 ]. Decrease in pH values was recorded in all fungal isolates differently in the culture media.…”

Cloning and Expression of Cellulosome-Integrating Protein from Aspergillus niger H1 Improves Phosphate Solubilization

“…Experiments proved that A. niger H1 exerted good effects on P solubilization and inhibited the transformation of soluble P to insoluble P. In this study, lactic acid was excreted and reached 377.9 μg mL -1 at 30 h in culture by A. niger H1 (Gong et al, 2014b). The expression of certain genes could secrete organic acid in the A. niger H1 genome.…”

Identification and glass biodeterioration of Chaetomium globosum TTHF1-3 isolated from optical instrument at Thai Hoa, Nghe An province

“…Nhiều công bố chứng minh các sản phẩm trao đổi chất của vi nấm như axit hữu cơ (tạo pH thấp phá hỏng bề mặt kính), polysaccharide ngoại bào (EPS) (giúp nấm sợi bám dính, tạo biofilm, gây mờ kính,...) là tác nhân gây hại đến bề mặt chi tiết kính [5,7]. Một số chủng vi nấm gây hại kính cửa sổ có khả năng sinh tổng hợp nhiều loại axit hữu cơ khác nhau như axit oxalic, axit citric [5,8,9] và chelate hoá mạnh các kim loại nặng như Ca, Cd, Co, Cu, Mg, Mn, Sr, Zn, Ni và Pb trong vật liệu kính [5,10]. Hơn nữa, khả năng sinh EPS là đặc tính quan trọng của nấm sợi gây hại chi tiết kính, giúp cho các nhóm nấm sợi cơ hội phát triển, lan rộng trên bề mặt, tăng khả năng phá huỷ vật liệu kính [11,12].…”

“…Sau 72 giờ nuôi cấy, giá trị pH sau nuôi cấy giảm mạnh nhất ở môi trường MT1 (từ pH 6,5 xuống pH 3,1). Các nghiên cứu cho thấy, nấm gây hại trên vật liệu kính có khả năng làm giảm pH môi trường nuôi cấy và phổ sinh axit hữu cơ cao hơn nấm phân lập từ nước, nội sinh, đất [5,8,9]. Trên vật liệu kính, các chi Penicillium, Aspergillus và Cladosporium được tìm thấy khá phổ biến nhất gây ăn mòn và sinh nhiều loại axit hữu cơ formic, citric, acetic, oxalic, gluconic và itaconic [34,35].…”